package stringadd;

public class StringAdd {
	public static String addStrings(String x, String y) {
		if (x == null || y == null) {
			throw new IllegalArgumentException();
		}
		return x + y;
	}


    public static int getSrings(String a)
    {
		if (a == null) {
			throw new IllegalArgumentException();
		}
		return a.length();
	}
	
    public static String replaceString(String a, String b, String c) {
		if (a == null || b == null || c == null) {
			throw new IllegalArgumentException();
		}

		return a.replaceAll(b, c);

	}
}
    
    
